Lignosulfonate coated calcium chloride

ABSTRACT

Ice-melt compositions including calcium chloride coated with a lignosulfonate material are disclosed. The ice-melt compositions can be useful as ice-melt products with improved safety. Also disclosed are methods of melting ice using an ice-melt composition and methods of making an ice-melt composition.

REFERENCE TO RELATED APPLICATIONS

The present application is a national stage application under 35 U.S.C.§ 371 of International Application No. PCT/US17/27591, filed Apr. 14,2017, which claims the priority of U.S. provisional application Ser. No.62/322,646, filed Apr. 14, 2016, both entitled LIGNOSULFONATE COATEDCALCIUM CHLORIDE, and hereby incorporates the same applications hereinby reference in their entireties.

TECHNICAL FIELD

The present disclosure generally relates to calcium chloride productsfor melting ice.

BACKGROUND

Calcium chloride is commonly used as an ice-melt material to melt iceand snow on sidewalks, roads, driveways, etc. For example, calciumchloride pellets are among the most effective ice-melting products onthe market. When calcium chloride dissolves in water, it releasesconsiderable heat as part of an exothermic process. The heat enablescalcium chloride to be an effective ice-melt material at temperatures aslow as about −25° F. Compared to other ice-melting compounds, such assodium chloride, calcium chloride can melt ice faster and at lowertemperatures. Calcium chloride is also less corrosive and less harmfulto vegetation than sodium chloride.

However, calcium chloride is also known to be hygroscopic(water-absorbing). This can be a problem for people or animals that comeinto contact with calcium chloride. Specifically, because calciumchloride is strongly water/moisture-absorbing, when a person or animal(e.g., pet) comes into contact with calcium chloride, they canexperience harmful effects, such as irritation to their skin, mouth, oreyes.

SUMMARY

According to one embodiment, an ice-melt composition includes coatingparticles. Each of the coated particles includes a core and a coating atleast partially surrounding the core. The core includes calciumchloride. The coating includes a lignosulfonate material. The coatedparticles include about 0.1% to about 5%, by weight, of thelignosulfonate material.

According to another embodiment, an ice-melt composition includescoating particles. Each of the coated particles includes a core and acoating at least partially surrounding the core. The core includescalcium chloride. The coating consists essentially of a lignosulfonatematerial. The coated particles include about 0.1% to about 5%, byweight, of the lignosulfonate material.

According to another embodiment, an ice-melt composition includescoating particles. Each of the coated particles includes a core and acoating at least partially surrounding the core. The core includescalcium chloride. The coating consists essentially of a lignosulfonatematerial and a colorant. The coated particles include about 0.1% toabout 5%, by weight, of the lignosulfonate material.

According to another embodiment, a method of melting ice includesapplying an ice-melt composition to ice. The ice melt compositionincludes coated particles. Each of the coated particles includes a coreand a coating at least partially surrounding the core. The core includescalcium chloride. The coating includes a lignosulfonate material.

According to another embodiment, a method of making an ice-meltcomposition includes providing a plurality of particle cores and coatingeach of the plurality of particle cores with a liquid coatingcomposition to form an ice-melt composition. Each of the particle coresincludes calcium chloride. The liquid coating composition includes alignosulfonate material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cross-section view of a calcium chloride pelletaccording to one embodiment.

FIG. 2 depicts a cross-section view of a spray coating apparatus tocoating calcium chloride according to one embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Ice-melt compositions are disclosed herein which can be useful formelting ice on various surfaces, including surfaces that people walk ordrive on, such as sidewalks, driveways, and roads. The ice-meltcompositions can include particles of an ice-melting material.

The particles of an ice-melting material can have any suitable size,shape, and dimensions for ice-melting applications. For example, theparticles can be in the form of pellets, mini-pellets, granules, prills,nuggets, briquettes, or other various forms. The particles can also haveany suitable particle size distribution. As can be appreciated, moreuniform particle size distribution can be desirable, for example, tofacilitate handling and use of the ice-melt compositions (e.g., tofacilitate use with salt spreaders). In certain embodiments, about 50%or more of the particles can have a size, as measured along the longestaxis, in the range of about 0.5 mm to about 5 mm. For example, suitableparticles can have a size along the longest axis, of about 0.5 mm, about0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1.0 mm, about1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm, about1.6 mm, about 1.7 mm, about 1.8 mm, about 1.9 mm, about 2.0 mm, about2.1 mm, about 2.2 mm, about 2.3 mm, about 2.4 mm, about 2.5 mm, about2.6 mm, about 2.7 mm, about 2.8 mm, about 2.9 mm, about 3.0 mm, about3.1 mm, about 3.2 mm, about 3.3 mm, about 3.4 mm, about 3.5 mm, about3.6 mm, about 3.7 mm, about 3.8 mm, about 3.9 mm, about 4.0 mm, 4.1 mm,about 4.2 mm, 4.3 mm, 4.4 mm, about 4.5 mm, about 4.6 mm, about 4.7 mm,about 4.8 mm, about 4.9 mm, or about 5.0 mm. In certain embodiments,less than about 30% of the particles can have a size, as measured alongthe longest axis, larger than about 5 mm.

In certain embodiments, the particles, such as pellets or granules, canbe sized using a sieve. For example, particles can be larger than about35 mesh (US sieve size), including, about 35 mesh, about 30 mesh, about25 mesh, about 20 mesh, about 15 mesh, about 10 mesh, about 5 mesh, orabout 3.5 mesh. In certain embodiments, the particles can be sizedbetween about 35 mesh and about 3.5 mesh, including, for example, atabout 35 mesh, at about 30 mesh, at about 25 mesh, at about 20 mesh, atabout 15 mesh, at about 10 mesh, at about 5 mesh, or at about 3.5 mesh.In certain embodiments, about 60%, or more, of the particles can besized larger than about 35 mesh, including, for example, about 60% ormore, about 65% or more, about 70% or more, about 75% or more, about 80%or more, about 85% or more, about 90% or more, or about 95% or more ofthe particles. In certain embodiments, about 40% or less of theparticles can be sized larger than about 3.5 mesh, including, forexample, about 40% or less, about 35% or less, about 30% or less, about25% or less, about 20% or less, about 15% or less, about 10% or less, orabout 5% or less of the particles.

In certain embodiments, the particles of an ice melting composition caninclude a core and a coating disposed at least partially around, orabout, the core. In certain embodiments, the core can include calciumchloride and the coating can include a lignosulfonate material. Thecoating can fully surround or encapsulate the core, or the coating canonly partially surround or coat the core.

In certain embodiments, the ice-melt composition can include any amountof calcium chloride suitable for melting ice. For example, in certainembodiments, the ice-melt compositions can include additional materialsintermixed with the particles of an ice-melting material. Alternatively,or additionally, the ice-melt compositions can include particles withvarying amounts of calcium chloride. With respect to the ice-meltcomposition in aggregate (i.e., as a bulk mass), the quantity of calciumchloride in the composition can range from about 60% to about 99.9% byweight. For example, the amount, by weight, of the calcium chloride inan ice-melt composition can be about 60%, about 62.5%, about 65%, about67.5%, about 70%, about 72.5%, about 75%, about 77.5%, about 80%, about82.5%, about 85%, about 87.5%, about 90%, about 91%, about 92%, about93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%,about 99.5%, or about 99.9%.

With respect to the individual particles of the ice-melt composition,each individual particle can also include varying amounts of calciumchloride. For example, each particle can include about 60% to about99.9% calcium chloride by weight of the particle. In variousembodiments, the particle can include about 60%, about 62.5%, about 65%,about 67.5%, about 70%, about 72.5%, about 75%, about 77.5%, about 80%,about 82.5%, about 85%, about 87.5%, about 90%, about 91%, about 92%,about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about99%, about 99.5%, or about 99.9% calcium chloride by weight of theparticle.

As can be appreciated, lignosulfonate is a widely-available byproduct ofwood pulp processing. Specifically, wood from trees is composed mainlyof three components: cellulose, hemicellulose, and lignin. In wood pulpprocessing, lignin can be sulfonated to form a water-soluble compoundextractable from the pulp. As a result of the sulfonation, thesolubilized lignosulfonates can be separated from the insolublecellulose. These lignosulfonate byproducts can encompass a wide range ofmolecular weights and chemistries. Applicant has found that certainlignosulfonate materials can be used to coat calcium chloride to improvethe safety profile of calcium chloride without impairing the use ofcalcium chloride for ice removal.

Generally, suitable lignosulfonate materials to coat the particlesdescribed herein can have a molecular weight in the range of about 1,000to about 20,000. In certain embodiments, the lignosulfonate materialscan be used in a salt form. For example, suitable lignosulfonate saltscan include calcium lignosulfonate, sodium lignosulfonate, ammoniumlignosulfonate, or a combination thereof.

In certain embodiments, each particle can include an amount oflignosulfonate material in the range of about 0.1% to about 10%, byweight, of the particle. For example, each particle can include about0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, 0.6%, about 0.7%,about 0.8%, about 0.9%, about 1%, about 1.1%, about 1.2%, about 1.3%,about 1.4%, about 1.5%, about 1.6%, about 1.7%, about 1.8%, about 1.9%,about 2.0%, about 2.1%, about 2.2%, about 2.3%, about 2.4%, about 2.5%,about 2.6%, about 2.7%, about 2.8%, about 2.9%, about 3.0%, about 3.1%,about 3.2%, about 3.3%, about 3.4%, about 3.5%, about 3.6%, about 3.7%,about 3.8%, about 3.9%, about 4.0%, about 4.1%, about 4.2%, about 4.3%,about 4.4%, about 4.5%, about 4.6%, about 4.7%, about 4.8%, about 4.9%,about 5%, about 5.5%, about 6.5%, about 7.0%, about 7.5%, about 8.0%,about 8.5%, about 9.0%, about 9.5%, or about 10%, by weight, of alignosulfonate material. In certain embodiments, each particle caninclude less than about 3%, by weight, of a lignosulfonate material; incertain embodiments, each particle can include about 1% to about 3%, byweight, of a lignosulfonate material; and in certain embodiments, eachparticle can include about 1.5% to about 2%, by weight, of alignosulfonate material.

In certain embodiments, the ice-melt compositions described herein caninclude other ice-melting materials, such as rock salt (sodiumchloride), potassium chloride, and/or urea. The ice-melt compositionscan also, or alternatively, include non-slip aggregates, such as sand,cinders, and/or crushed limestone. As can be appreciated, otheradditives and compounds can also be added including colorants and dryingadditives.

In certain embodiments, an ice-melt composition can include a coatedparticle core consisting essentially of calcium chloride.

In certain embodiments, an ice-melt composition can include a coatedparticle core that includes calcium chloride and a coating over thecore, where the coating consists essentially of a lignosulfonatematerial. In certain embodiments, the coating over the core can consistessentially of a lignosulfonate material, and additionally a colorantand/or a drying additive. In certain embodiments, the colorant can bewater-soluble.

In certain embodiments, the drying additive can be a finely powderedwater-absorbent compound including, for example, precipitated silica,anhydrous magnesium sulfate, and/or diatomaceous earth.

In certain embodiments, the ice-melt compositions described herein donot include brewers condensed solubles (BCS), distillers condensedsolubles (DCS), and/or condensed corn steep liquid (CCSL).

The ice-melt compositions described herein can be more advantageous touse than calcium chloride ice-melt compositions known in the art. Incertain embodiments, the lignosulfonate material coating can reduce thehydroscopic properties of the composition as compared to the ice-meltcompositions known in the art. In such embodiments, the composition canadvantageously be used in environments where humans or animals may comeinto contact with the ice-melt composition, such as sidewalks,driveways, and roads.

Without being bound by theory, it is theorized that lignosulfonatematerials can hydrate a thin outer surface of the calcium chloride core.In combination with the coating provided by the lignosulfonate materialitself, such hydration can reduce the harmful effects caused by calciumchloride dissolving.

FIG. 1 depicts an exemplary coated calcium chloride pellet 10 of anice-melt composition. The coated calcium chloride pellet 10 includes acore 16 of calcium chloride and a coating 12 of calcium lignosulfonateabout the core 16. The coating 12 has a higher water content than thecalcium chloride core 16, which serves to hydrate a thin outer surface14 of the core 16. The hydration of the outer surface 14, along with thephysical barrier protection provided by the coating 12, can reduce theharmful or irritating effect of the calcium chloride pellet 10 when itcomes into contact with a person or animal. When applied to ice, thecoating 12 can dissolve and expose the calcium chloride core 16 to theice.

Methods of making an ice-melt composition as described herein are alsoprovided. In certain embodiments, the method includes: providing a coreincluding calcium chloride; and coating the core with a liquidcomposition including a lignosulfonate material. The lignosulfonatecoating can be applied onto the cores using any suitable technique, suchas conventional spraying coating techniques. As can be appreciated, thecoating process can be a batch process, a semi-batch process, or acontinuous process in certain embodiments.

The amount of lignosulfonate material in the coating liquid can beselected such that the liquid has a viscosity sufficiently low tofacilitate spraying or coating onto the core. In certain embodiments,the amount of the lignosulfonate material in the coating liquid can varyfrom about 1% to about 95% by weight of the coating liquid. For example,the coating liquid can include about 1%, about 2%, about 5%, about 10%,about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%,about 80%, about 85%, about 90%, or about 95% of a lignosulfonatematerial by weight of the coating liquid. In certain embodiments, thecoating liquid can include from about 20% to about 80% of thelignosulfonate material, for example, from about 25% to about 60% of thetotal weight of the coating liquid.

FIG. 2 depicts an example coating process. In FIG. 2, calcium chloridepellets 20 are placed into the chamber of a rotary mixer 22. The rotarymixer 22 is equipped with a spray nozzle 28 that is connected to a spraysolution tank 24 via a supply line 26. The spray solution tank 24 isfilled with a lignosulfonate coating solution, which is applied onto thecalcium chloride pellets 20 by a spray 30 generated by the spray nozzle28 while the rotary mixer 22 is turning.

Example 1

930 grams of calcium chloride pellets (SAFE STEP® Extreme 7300) wereplaced into a table top rock polisher tumbler. A spray solution was madeby mixing Norlig A (a 58% calcium lignosulfonate solution in water fromLIGNOTECH USA®) with water at a 1:1 weight to weight ratio. Theresulting spray solution contained about 29% calcium lignosulfonate byweight. The spray solution was filled into a pressure bottle. With thetumbler activated, 70 grams of the spray solution was sprayed onto thecalcium chloride pellets using an 8002 nozzle at 40 pounds per squareinch (“psi”). The total amount of spray solution loaded onto the calciumchloride pellets was 7% by weight (5% water, plus 2% calciumlignosulfonate).

The coated material initially had a wet appearance, but dried afterabout 5 minutes. The material was warm from the heat of hydration of thecalcium chloride. The product was spread out onto a tray and placed inan oven at 104° C. for 30 minutes to remove surface tackiness. Thecoated material had a uniform tan color and the he calciumlignosulfonate coating weight was determined to be 2% by weight of thepellet. When applied onto a patch of outdoor ice, the coated calciumchloride pellets melted the ice at about the same speed and rate as theuncoated calcium chloride pellets (SAFE STEP® Extreme 7300). Theseresults demonstrated that the coated calcium chloride pellets canprovide improved safety without significantly compromising ice meltingperformance.

Example 2

144.53 pounds of calcium chloride pellets (Occidental Chemical Corp.)were placed into a Munson mixer equipped with a 650067 spray nozzle. Aspray solution was made by mixing 680.39 grams of water and 1769.01grams of Norlig A. The resulting spray solution contained 41% calciumlignosulfonate by weight. This spray solution was divided into equalportions into three pressure bottles. The bottles were then heated toabout 120° F.

After starting the mixer, the first bottle was connected to the spraynozzle and its contents were sprayed out at 40 psi for a spray time of 2minutes 45 seconds. The temperature of the calcium chloride materialtaken after 2 minutes and 8 minutes from the start of spraying was 77.7°F. After 10 minutes, the second bottle was connected to the spray nozzleand its contents were sprayed out at 40 psi for a spray time of 2minutes 35 seconds. The temperature of the calcium chloride materialtaken at 2 minutes and 8 minutes from the start of the second bottlespraying was 87.2° F. After 10 minutes, the third bottle was connectedto the spray nozzle and its contents were sprayed out at 40 psi for aspray time of 2 minutes 35 seconds. The temperature of the calciumchloride material was 94.0° F. and 93.8° F. at 2 minutes and 8 minutesrespectively from the start of the third bottle spraying. After 5minutes, 34.02 grams of precipitated silica (HI-SIL®233) was added tothe batch and the material was allowed to cure for an additional 15minutes before removing from the mixer. The still warm material was freeflowing and tan in color. The material contained 1.5% by weight calciumlignosulfonate coating by weight of the particle.

It should be understood that every maximum numerical limitation giventhroughout this specification includes every lower numerical limitation,as if such lower numerical limitations were expressly written herein.Every minimum numerical limitation given throughout this specificationwill include every higher numerical limitation, as if such highernumerical limitations were expressly written herein. Every numericalrange given throughout this specification will include every narrowernumerical range that falls within such broader numerical range, as ifsuch narrower numerical ranges were all expressly written herein.

Every document cited herein, including any cross-referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests,or discloses any such invention. Further, to the extent that any meaningor definition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in the document shallgovern.

The foregoing description of embodiments and examples has been presentedfor purposes of description. It is not intended to be exhaustive orlimiting to the forms described. Numerous modifications are possible inlight of the above teachings. Some of those modifications have beendiscussed and others will be understood by those skilled in the art. Theembodiments were chosen and described for illustration of ordinary skillin the art. Rather it is hereby intended the scope be defined by theclaims appended various embodiments. The scope is, of course, notlimited to the examples or embodiments set forth herein, but can beemployed in any number of applications and equivalent articles by thoseof hereto.

What is claimed is:
 1. An ice-melt composition comprising: coatedparticles, wherein each coated particle comprises: a core comprisingcalcium chloride; and a coating at least partially surrounding the core,the coating consisting essentially of a lignosulfonate and an optionalcolorant; and wherein the coated particles comprise about 60% to about99.9%, by weight, of the calcium chloride and about 0.1% to about 5%, byweight, of the lignosulfonate material.
 2. The ice-melt composition ofclaim 1, wherein the lignosulfonate material comprises calciumlignosulfonate, sodium lignosulfonate, ammonium lignosulfonate, ormixtures thereof.
 3. The ice-melt composition of claim 1, wherein thecoated particles are pellets, granules, or mixtures thereof.
 4. Theice-melt composition of claim 1, wherein about 60% or more of the coatedparticles are sized at about 35 mesh or greater.
 5. The ice-meltcomposition of claim 1, wherein about 40% or less of the coatedparticles are sized at about 3.5 mesh or greater.
 6. The ice-meltcomposition of claim 1, wherein the lignosulfonate material is solublein water.
 7. The ice-melt composition of claim 1, wherein the coatingfurther consists essentially of the colorant.
 8. The ice-meltcomposition of claim 7, wherein the colorant is water-soluble.
 9. Theice-melt composition of claim 1, wherein the lignosulfonate material atleast partially hydrates the calcium chloride.
 10. An ice-meltcomposition comprising: coated particles, wherein each coated particlecomprises: a core consisting essentially of calcium chloride; and acoating at least partially surrounding the core, the coating consistingessentially of a lignosulfonate material, an optional colorant, anoptional drying additive, an optional non-slip aggregate, and anoptional ice-melting material selected from the group consisting of achloride salt and urea; and wherein the coated particles comprise about0.1% to about 5%, by weight, of the lignosulfonate material.
 11. Theice-melt composition of claim 10, wherein the lignosulfonate materialcomprises calcium lignosulfonate, sodium lignosulfonate, ammoniumlignosulfonate, or mixtures thereof.
 12. The ice-melt composition ofclaim 10, wherein the particles are pellets, granules, or mixturesthereof.
 13. The ice-melt composition of claim 10, wherein about 60% ormore of the coated particles are sized at about 35 mesh or greater. 14.The ice-melt composition of claim 10, wherein about 40% or less of thecoated particles are sized at about 3.5 mesh or greater.
 15. Theice-melt composition of claim 10, wherein the lignosulfonate material issoluble in water.
 16. An ice-melt composition comprising: coatedparticles, wherein each coated particle comprises: a core consistingessentially of calcium chloride; and a coating at least partiallysurrounding the core, the coating consisting of a lignosulfonatematerial, a colorant, an optional drying additive, an optional non-slipaggregate, and an optional ice-melting material selected from the groupconsisting of a chloride salt and urea; and wherein the coated particlescomprise about 0.1% to about 5%, by weight, of the lignosulfonatematerial.
 17. The ice-melt composition of claim 16, wherein thelignosulfonate material comprises calcium lignosulfonate, sodiumlignosulfonate, ammonium lignosulfonate, or mixtures thereof.
 18. Theice-melt composition of claim 16, wherein the particles are pellets,granules, or mixtures thereof.
 19. The ice-melt composition of claim 16,wherein about 60% or more of the coated particles are sized at about 35mesh or greater.
 20. The ice-melt composition of claim 16, wherein about40% or more of the coated particles are sized at about 3.5 mesh orgreater.
 21. The ice-melt composition of claim 16, wherein thelignosulfonate material is soluble in water.
 22. The ice-meltcomposition of claim 16, wherein the colorant is water soluble.